holoacardius

A separate, grossly defective twin lacking a heart of its own, its blood supply being dependent on a shunt from the placental circulation of a more nearly normal twin; a placental parasitic twin or omphalosite. Cf.:acardius. [holo- + G. a- priv. + kardia, heart]

- h. acephalus a h. also lacking a head.

- h. amorphus a h. in which the body of the parasite is represented by only a shapeless mass. SEE ALSO: anideus.

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holo·acar·di·us (hōl″o-ə-kahrґde-əs) [holo- + acardius] a separate, monozygotic twin represented by a more or less shapeless and unidentifiable mass; the vascular systems of the two fetuses are connected, and the circulation is accomplished solely by the heart of the well-developed twin.